Screen Dump Station System For Disposing Of Spent Drilling Mud

ABSTRACT

A processing system for a slurry material. The system has a vibratory screen disposed atop an open-topped tank. A travel path for a vehicle is disposed directly above the screen and the tank. Slurry material dumped from the vehicle onto the screen is separated at the screen into a particulate-rich stream and a fluid-rich stream. The fluid-rich stream may be pumped to a cleaner so that it may be stored and re-used as drilling fluid. The screen may be a conveyor which removes the particulate-rich stream from above the tank.

FIELD

The present invention relates to a method for disposing of spentdrilling mud.

SUMMARY

The invention is directed to a system. The system comprises a vehicletravel path defined by a first ramp, a second ramp, and a dumpingstation. The dumping station is disposed between the two ramps andcomprises a screen and a tank. The tank is disposed directly beneath thescreen and the vehicle travel path. A slurry material flowpath isdefined above and on the screen. The screen separates the slurrymaterial into a particulate-rich flowpath and a fluid-rich flowpath.

The invention is also directed to a method. The method comprisessupporting at least a portion of a vehicle on a bridge havingspaced-apart tracks. A slurry is received from the vehicle at a screendisposed between the spaced-apart tracks. The slurry is separated into afluid-rich portion and a particulate-rich portion with the screen. Thefluid-rich portion is received in a tank disposed directly below thescreen. At least some of the fluid-rich portion is cleaned to prepare adrilling fluid.

The invention is also directed to an apparatus. The apparatus comprisesa bridge, a screen, a vibrator, a tank, and a conveyor. The bridge has aspaced pair of tracks. The screen is disposed between the pair oftracks. The vibrator is operatively connected to the screen. The tank isdisposed directly below the screen and the tracks. The conveyor isdisposed at an end of the screen.

The invention is also directed to a system. The system comprises aforward travel path, a screen, and an open-topped tank. The forwardtravel path is for a wheeled vehicle and includes a partially openplatform. The screen is situated beneath the platform. The open-toppedtank is situated beneath the screen.

The screen may be a moving screen conveyor, which deposits material overa side of the tank or at a chute.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overhead isometric view of a material processing systemwith a vacuum truck and trailer disposed at a dumping station.

FIG. 2 is an overhead isometric view of the material processing systemof FIG. 1 with the truck and trailer removed.

FIG. 3 is an overhead view of a dumping station for use with the systemof claim 1.

FIG. 4 is an isometric view of a vibratory screen frame for use with thedumping station of FIG. 3.

FIG. 5 is a sectional side view of the dumping station of FIG. 3.

FIG. 6 is a sectional front view of the dumping station of FIG. 3.

FIG. 7 is a front view of the system of FIG. 1.

FIG. 8 is an overhead plan view of the system of claim 1 connected to anauxiliary cleaner and filling station.

FIG. 9 is a process flow chart showing the flow path of slurry materialdeposited in the system.

FIG. 10 is an overhead isometric view of a below-ground materialprocessing system.

FIG. 11 is a sectional side view of an alternative dumping stationhaving a screen conveyor

DETAILED DESCRIPTION

Drilling fluid is utilized in underground construction operations, suchas horizontal directional drilling, to form an underground constructionlocation used to dislodge the underground material. This materialtravels up a borehole as “spent mud”. The spent mud may be removed fromthe work site and collected in a vacuum tank.

Spent mud presents disposal problems. The spent mud contains theoriginal drilling fluid—a valuable material for use in drillingoperations. However, dislodged soil, rocks, and other debris is presentin the spent mud, creating a slurry that is inappropriate for immediatereuse.

Further, environmental regulations in some jurisdictions make thedeposit of wet material on the ground inappropriate. So while largerparticulates contained in a spent mud slurry may be valuable as groundfill, it often cannot be placed in a landfill while wet. Therefore, asystem to easily deposit spent mud in a way that removes and driesparticulates while recycling material for reuse as drilling mud isadvantageous.

Referring to FIG. 1, a material processing system 10 is shown. Thesystem comprises a processing tank 12, a material conveyer 14, one ormore dumping stations 16, and a plurality of ramps 18. As shown, thesystem 10 comprises two dumping stations 16, each with a pair or ramps18 leading to a corresponding dumping station 16. The dumping stations16 are accessible by a pedestrian from the ground by one or morecatwalks 19 supported next to at least one of the plurality of ramps 18.

Each dumping station 16, along with the ramps 18, defines a vehicletravel path that may accommodate a vehicle tank 20. As shown, thevehicle tank 20 may be supported by a truck 21 or trailer 22. Each truck21 or trailer 22 may also comprise auxiliary tanks 17 for transportingwater and clean drilling mud to a drill site.

The tank 12 may be free-standing, as shown in FIG. 1, or may be totallyor partially below-ground. By providing a ramp 18 on each side of thedumping stations 16, a truck 21 or trailer 22 may move entirely in onedirection to a dumping station 16. An entire length of the system 10,comprising two ramps 18 and a dumping station 16, may be traversed by atank 20. FIG. 10 shows the system 10 of FIGS. 1-7 in a below-groundconfiguration.

With reference to FIG. 2, the system 10 is shown with the vehicle tanks20 removed. As shown, the dumping stations 16 comprise a bridge 24 and agap 26. The bridge 24 may comprise two tracks 25 roughly equivalent tothe wheel base of the truck 21 or trailer 22. The gap 26 is disposedbetween the two tracks 25 and allows dumping of material from a vehicletank 20 positioned at the dumping station 16 without obstruction. A gap26 of approximately four feet may be satisfactory to provide clearancebetween the tracks 25. In this way, the tracks 25 and gap 26 provide apartially open platform 27 for dumping material from the vehicle tank 20to the processing tank 12. FIG. 10 shows a similar dumping station 16below ground.

One or more shields 28 may be provided at an end of the dumping station16 to deflect material from a tank away from a ramp 18 and into theprocessing tank 12. Preferably, a shield 28 may be provided at each endof the dumping station 16 such that identical operation is possible ineither direction of tank 20 travel. The shield 28 minimizes the amountof material from the vehicle tank 20 that fails to enter the processingtank 12.

With reference now to FIGS. 3-4, the processing tank 12 comprises ascreen 30. The screen 30 is preferably located within the gap 26. Asshown, the screen 30 is recessed below the level of the tracks 25. A“cattle guard” (not shown) or other structural protection may beprovided above the screen 30 to prevent damage from vehicles and fallingdebris.

The screen 30 may be vibrated or conveyed toward the material conveyer14. As shown in FIG. 4, a vibrator 31 and the screen 30 are supported byan integral screen frame 29. The deposited material is conveyed due tovibration of the vibrator 31 imparted on the screen frame 29 and due toa slope of the screen 30. The screen 30 preferably has a mesh size (notshown) that allows fine particulates and liquids, such as that found inbentonite drilling fluid, to pass through the screen. Courseparticulates are transported to the conveyer 14 (FIGS. 1-2). The meshsize is preferably three eighths of an inch, though other mesh sizes maybe utilized depending on the requirements of the separation process.

While a vibrator 31 is shown in the figures for use with the screen 30,it should be understood that a conveyable screen system such as afertilizer chain may be utilized without departing from the spirit ofthe invention. Additionally, the screen 30 may be static, and a chain orother apparatus can drag particulates across the screen for disposal onthe conveyor 14 or otherwise.

Course particulates unable to pass through screen 30 are conveyed from adump end 32 of the screen to a chute end 34. The material conveyor 14 isdisposed near the lower chute end 34 of the screen 30. A chute 36 isdisposed at the chute end 34 of the screen 30. The chute 36 angles downfrom the chute end 34 to the material conveyer 14 (FIGS. 1-2). Thescreen 30 may also be tiltable, such that the slope of the screen fromthe dump end 32 to the chute end 34 may be increased after the slurryhas remained on the screen for an acceptable working time to urge theparticulates to the chute 36.

The screen 30 may be modified to increase or decrease the working timeof the material deposited thereon. For example, increasing the slopefrom dump end 32 to chute end 34 decreases working time for material,which increases the processing capacity of the screen 30 but results inwetter material in the material conveyer 14. Conversely, a “flatter”screen 30 results in more working time, which may decrease availablethroughput but improve separation, resulting in drier particulates inthe conveyer 14. Solids removed by the conveyer 14 are usuallyconsidered dry enough for typical disposal in a landfill or on a surfaceof the ground.

A platform 38 is disposed between the dumping stations 16 to allowservicing of the screens 30, vibrators 31, and processing tank 12components. The platform 38 is accessible via the catwalk 19 (FIG. 1).

With reference now to FIG. 5, the processing tank 12 of the systemcomprises a sloped portion 40. Remaining fluid falls through the screen30 into the processing tank 12. The fluid travels down the slopedportion 40 to the bottom of the tank 12. Agitators (not shown) or othermechanisms may be used to encourage the fluid to settle in the bottom ofthe tank 12. The bottom of the tank 12 may be located between two slopedsides as shown in FIG. 5. Alternatively, one sloped side may urge thefluid to one side of the tank 12.

With reference to FIG. 6, a cross-section of the tank 12 is shown. Thetank's sloped bottom 40 not only slopes towards the bottom of the tank(FIG. 5) but also to a center location 43 between the two dumpingstations 16. At least one pump 42 is disposed at the center location 43within the tank 12. One of skill in the art will appreciate that thecenter location 43 may preferably be the lowest point within the tank.The pump 42 may preferably be a sump.

The pump 42 displaces fluid that settles at the bottom of the tank 12and forces it into a conduit 44. Fluid in the conduit 44 may be suitablefor reuse, or may be further processed.

As shown in FIGS. 1-7, the system is free-standing, having at least onedumping station 16, and at least two outlets. The outlets are theconveyer 14 and the conduit 44. While it may be preferable to providethe system 10 at a permanent location, the system may be modular andportable. A modular system 10 may be customizable with additionaldumping stations 16 and higher capacity conveyers 14, screens 30, andpumps 42. Additionally, portions of the system 10, such as the tank 12and ramps 18, may be portable such that the system can be disassembled,moved, and reassembled at an advantageous location. In all theembodiments described herein, the screen 30 and tank 12 are disposeddirectly below the vehicle travel path.

With reference to FIG. 11, an alternative embodiment of the dumpingstation 16A is shown with a screen conveyor 150 in place of the screen30. The screen conveyor comprises an endless screen 152, a structuralframe 154, and a pair of rotating hubs 156. The frame 154 providesstructural strength to the screen conveyor 150 and separation for thetop and bottom surfaces of the endless screen 152. The endless screen152 is supported about the rotating hubs 156. As the hubs 156 rotate,particulate-rich matter disposed on the endless screen 152 is movedtowards a side of the tank 12, either at a chute 36 or other location.This provides ease of removal and clears the area above the tank forfurther processing from additional trucks 21 or trailers 22.

As shown in FIG. 11, the chute 36 is disposed at a chute end 34 of thetank 12. The chute end 34 is preferably opposite the shield 28 and thusthe location that material is dumped. This increases the transit time ofmaterial on the screen conveyor 150. The more time material is on thescreen conveyor 150, the more recovered fluid drains from particulatematter and into the tank 12 for recovery.

With reference now to FIG. 8, an additional cleaner 60 is showndownstream of the system 10. The cleaner 60 may comprise a reclaimer 62,a mixer 64, and a mud tank 66. As shown, the cleaner 60 comprises tworeclaimers 62. Mud from the conduit 44 is deposited at the reclaimer 62,which may be any known mesh reclaimer system, including that found inU.S. Pat. No. 9,662,599, issued to Sewell, the contents of which areincorporated herein by reference in its entirety.

The reclaimer 62 (or plurality of reclaimers), as shown in greaterdetail in FIG. 10, further separates liquid and solid particulate fromthe conduit 44 through screen separation. Mesh sizes within thereclaimer 62 may be less than an eighth of an inch. If a series ofreclaimers 62 are used, each successive reclaimer 62 may comprise asmaller mesh size. Larger particulate matter may be removed from thesystem and dried. Small particulates removed from the reclaimer 62 maybe reintroduced upstream, dried for use as fill, or discarded.

With reference again to FIG. 8, fluid from the reclaimer 62 is pumpedinto the mixer 64. The fluid is monitored to determine whether itsproperties are similar to new, clean, ready to use drilling fluid. Ifexcess particulate passes through the reclaimer 62 into the mixer, aportion of the fluid in the mixer may be returned to the reclaimersystem for further processing. When fluid properties are appropriate,clean, ready to use drilling fluid is then stored in the mud tank 66with agitators to keep the fluid in ready to use condition.

Adjacent to the mud tank 66 is a fresh water tank 68. Both the mud tank66 and the fresh water tank 68 are connected to a pumping station 70which can be used to re-fill the now empty auxiliary tanks 17 on a truck21 or trailer 22 (FIG. 1).

Alternatively, a centrifuge (not shown) may aid in cleaning fluid in themud tank 34. Changes may be made to this system without departing fromthe spirit of the invention. For example, the entire system 10 may becomputer controlled to automate fluid flow and leveling from tank totank. A speed of the conveyer 14 and level of the screen 30 may bemodified to increase or decrease working time for material.

With reference to FIG. 9, the flow of slurry material deposited into thesystem 10 is shown. Slurry is released at 100 by the vehicle tank 20,initiating a slurry material flowpath 102. The slurry material flowpath102 extends to and terminates at the screen 30. Slurry material isseparated at 103 by the screen 30 into a particulate-rich flowpath 104and a fluid flowpath 105. It should be understood that the fluid-richflowpath 105 will contain entrained particulates. The fluid-richflowpath 105 is distinguished from the particulate-rich flowpath 104 bythe presence of most of the fluid from the slurry flowpath 102 and asmaller average particle size.

The particulate-rich flowpath 104 is conveyed away from the processingtank 12 by a conveyor 14 at 106. The particulates in theparticulate-rich flowpath may be disposed of or re-used as fill at 108.

The fluid-rich material is pumped at 110 to the auxiliary cleaner 60 bythe pump 42. Further cleaning of the fluid-rich material occurs in theauxiliary cleaner 60 at 105, separating the fluid-rich stream 105 into adrilling fluid stream 113 and a small particulate-rich stream 114. Asdescribed with reference to FIG. 8, the auxiliary cleaner 60 maycomprise reclaimers 62 and mixers 64. The auxiliary cleaner 60 may alsoinclude centrifuges (not shown) and other known separators.

The drilling fluid stream 113 terminates at the mud tank 66, where it isstored for re-use at 116. The small particulate stream 114 may bereintroduced within the auxiliary cleaner 60 or disposed at 118, eitherwith the particulate-rich stream 104 or otherwise.

The scope of the claims should not be limited by the preferredembodiments set forth in the examples, but should be given the broadestinterpretation consistent with the description as a whole.

1. A dumping station for receiving material from a transport vehicle,the dumping station comprising: a tank for receiving material dischargedfrom a transport vehicle, the tank defined by a first dimension and asecond dimension substantially perpendicular to the first dimension,wherein the first dimension is greater than the second dimension; spacedapart first and second tracks for supporting transport vehicles,disposed in a direction substantially parallel to the second dimension;and a screen disposed above the tank and configured to receive a slurrymaterial flowpath from the transport vehicle and to separate the slurrymaterial flowpath into a particulate-rich flowpath and a recoveredfluid-rich flowpath.
 2. The dumping station of claim 1 furthercomprising a conveyor extending proximate the tank to remove materialfrom the dumping station.
 3. The dumping station of claim 1 wherein thescreen comprises an endless belt disposed between rotating hubs.
 4. Thedumping station of claim 3 in which the screen is configured to carryparticulates along a portion of the particulate-rich flowpath.
 5. Thedumping station of claim 4 in which the portion of the particulate-richflow path provided by the screen is substantially parallel to the seconddimension.
 6. A system comprising: a first ramp; a second ramp; thedumping station of claim 5, wherein the first ramp, second ramp, anddumping station define a vehicle travel path that is orthogonal to thefirst dimension.
 7. A system comprising: a first ramp; a second ramp;the dumping station of claim 1, wherein the first ramp, second ramp, anddumping station define a vehicle travel path that is orthogonal to thefirst dimension.
 8. The dumping station of claim 1 further comprising ashield disposed above the tank.
 9. The dumping station of claim 8 inwhich the shield is configured for positioning above the tank betweenthe first and second tracks.
 10. A system comprising: a vehicle travelpath defined by a first ramp, a second ramp, and a dumping station,wherein the dumping station is disposed between the two ramps andcomprises: parallel tracks for supporting a vehicle interposed betweenthe first ramp and the second ramp along the vehicle travel path, theparallel tracks having a gap disposed therebetween; a screen disposedbetween the parallel tracks within and below the gap; and a tankdisposed directly beneath the screen and having an open upper endspanned by the parallel tracks.
 11. The system of claim 10 furthercomprising a shield disposed above a level of the tank and the paralleltracks and configured to be disposed between a path of the paralleltracks.
 12. The system of claim 10 in which the screen comprises anendless belt disposed between at least two rotating hubs.
 13. The systemof claim 10 in which: a slurry material flowpath is defined above and onthe screen; and the screen separates the slurry material flowpath into aparticulate rich flowpath and a recovered fluid-rich flowpath.
 14. Thesystem of claim 13 in which the screen has a movable surface, such thatthe particulate rich flowpath is at least partially on the movablesurface of the screen.
 15. The system of claim 13 in which the screen isstatic.
 16. A dumping station, comprising: a pair of spaced-apartparallel tracks configured for supporting a transport vehicle; a tankdisposed below the parallel tracks; a screen conveyor disposed betweenand below the parallel tracks and at least partially above the tank,comprising: a structural frame; first and second rotating hubs disposedat opposite ends of the structural frame; and an endless screensupported on the first and second rotating hubs and configured to berotated about the structural frame.
 17. The dumping station of claim 16further comprising a shield disposed above the tank and configured forpositioning between the parallel tracks.
 18. The dumping station ofclaim 16 in which the screen conveyor is configured to receive a slurrymaterial flowpath from a transport vehicle and to separate the slurrymaterial flowpath into a particulate-rich flowpath disposed on theendless screen and a recovered fluid-rich flowpath disposed within thetank.
 19. A method of using the system of claim 16 comprising: driving avehicle on the parallel tracks; thereafter, receiving the slurrymaterial flowpath from the vehicle at the screen conveyor; separatingthe slurry material flowpath into the recovered fluid-rich flowpath andthe particulate-rich flowpath; receiving the recovered fluid-richflowpath in the tank; and carrying the particulate-rich flowpath along alength of the endless screen.